Control for Optimized Kinesthetic Perception in Scaled Teleoperation of Soft Tissues

Abstract

This dissertation presents a control scheme for the optimization of kinesthetic perception with high position tracking, while guaranteeing the stability of scaled teleoperation systems. Three types of research themes are investigated to propose the new control scheme systemically. A new control scheme is developed for a bilateral teleoperation system for microsurgical applications in the first part of the dissertation. The main objective of the developed control scheme is to enhance operator’s kinesthetic perception. At first, kinesthetic perception is quantified, based on psychophysics, into two metrics which relate to the detection and discrimination of stimulus. Secondly, an improved scaled bilateral control system is developed using an impedance-shaping method. The proposed control method can increase the kinesthetic perception of the operator by shaping and magnifying the impedance transmitted to the operator. Simulation and experimental results show that kinesthetic perception is significantly enhanced for four-channel, position-position, and force-position control architectures. Applications like tele-microsurgical systems are prone to issues of stability and performance due to the interaction and information exchange between macro and micro world. Scaling factors used in these systems, therefore, have exceeding impacts on the stability and the performance. This dissertation, hence, analyzes the effects of the scaling factors in the third part, in an effort to increase the performance of the systems while maintaining the stability. Stability robustness is quantified using Llewellyn’s absolute stability criterion. Position tracking and the newly developed metrics of kinesthetic perception, which are important in telesurgical applications, are used to quantify the performance. The effects of the scaling factors are analyzed by using various combinations of the position and force scaling factors in addition to the human operator and environment impedanc...